arfink
Offline
Minneapolis

So, I have found someone who makes a 15kHz RGB to VGA scandoubler device. He originally made them for the Tandy Coco computer, but he's lately been working on mods to work with anything that can output a 15kHz RGB signal. That would include the Apple IIgs, Atari computers, Amigas, arcade boards, and probably more. He is sending me a kit to evaluate, and I'll do a full writeup when I get it, assemble it, and try it out! smile

His estimated cost per unit (fully assembled, with fancy plastic housing, etc.) is around $50 or so, which is quite a lot less than the next nearest RGB to VGA scandoubler. I'll provide more information when it arrives.

Last edited by arfink (Mar 8, 2010 10:33 pm)

LastKnight
Offline
Middlesbrough, UK

intrested....

octavialsilver
Offline
FERNDALE, MI, USA
LastKnight wrote:

intrested....

^ this.

arfink
Offline
Minneapolis

I also have (possibly) a big, pretty 23" LCD coming my way. Huzzah!

akira^8GB
Offline
New York City

Not so fast, dude.
What colour depth can this machine do? Before saying it works with an Amiga or Apple IIGS, you must say at what bit depth it's working.

For an Amiga 500, nothing smaller than 12-bit will do. For an A1200, you need 24-bit colour depth.

I didn't find a cheaper solution in 24 bit than this:
http://cgi.ebay.com/15Khz-RGB-CGA-Compo … 1c0bd53361

For the price given, I bet this converter only does 8-bit colour depth, which is probably fine for an 8-bit computer, but will look like ass on a Saturn, Amiga, and others.

Last edited by akira^8GB (Mar 9, 2010 5:37 pm)

arfink
Offline
Minneapolis

Well, I am not 100% sure on the color depth here... I got the board today though, and as soon as I get my sync splitter working I'm going to give it a try. I know for a fact it can do 16 bit color depth, at the very least. Also, on the Amiga, the 24 bit requirement is only for AGA modes, so don't get your boxers in a bundle. I'll ask him about it today, since he didn't give me a bunch of technical details, just the board.

Also, looking at the board, this is clearly NOT the kind of DIY kit the average person will be able to assemble, but still quite competitively priced (even fully assembled) if it can do what I think it can. I'd settle for 16 bit color depth. smile 'Cuz then it'll work with my IIgs and my Neo Geo!

Lastly, once I get a chance to try this baby out, I'll have pictures. Plenty of em!

akira^8GB
Offline
New York City

AGA modes = ANY A1200 software. Which is what real Amiga users use tongue
So it IS important.
I have a 12 bit Scandoubler on my A1200 and it's pretty useless.

If this does indeed do 24 bit on a 50 bucks budget, count me in for a unit.

arfink
Offline
Minneapolis

Well, he insisted it's %100 A1200 compatible, which I can only guess means at least 24 bit color... I'll know for sure a bit later though. Meanwhile, this thing's quite exciting, especially considering he sent me my (unfinished) unit for nothing. He's a very generous and helpful person. His name is Roy. I'll post his email contact after I have reviewed it so you all can contact him if you want to order one.

akira^8GB
Offline
New York City

That sounds really great man! keep us posted big_smile

athleos
Offline
Seattle, WA

I'm very interested in this as well.  I've been looking for schematics for one of these for quite a while.  I have one of those universal multi sync monitor cables from Best Electronics for my 1040STe but it doesn't work without a scandoubler...  real lame.

arfink
Offline
Minneapolis

Well, I got my bill of materials and schematic files all made up for my sync splitter. I found a public domain circuit from Lupine Systems which was done up in Protel EasyTracks, which was a mega pain to try to work with in Linux. I would up putting it through the old EZ package with DosBox and printing to a virtual printer to get post-script files which I could actually look at. The sync splitter is super easy, and not counting whatever protoboard you mount it on, it's got a grand total of 8 components:

2x 7400 chips
2x 1uF capacitors
2x 1k resistors
2x 1N4148 diodes (or whatever the heck kind of diode you want, really...)

After I convert the .PS files and clean them up, I'll post the pictures here so you can make a universal sync converter. It takes composite negative sync at 15kHz and can convert it to composite positive sync, negative horizontal and vertical sync, positive horizontal and vertical sync, and buffered negative composite sync.

arfink
Offline
Minneapolis

OK, quick update- I got my sync converter parts pretty much lined up so I can order, and I heard back from Roy and he says it's only 16 bit color depth conversion. Still, that's more than enough for me, and other than Amiga 1200 and some others which run at 24 or 32 bit color, it's plenty enough color. I'll post some pics once I got my sync converter running through the scandoubler.

Ogrim
Offline
Westcoast Norway

I would be interested in using this with my Atari STF. Not sure about the bit depths required, but I hope it can be used in low-resolution mode so I can run maxYMiser wink

arfink
Offline
Minneapolis

I should work... I think that the ST only goes up to 12 bit, so it's probably fine.

akira^8GB
Offline
New York City

Oh , there goes my excitement sad

arfink
Offline
Minneapolis

Yeah, I know. Still, it'll work great for what I want. Looking at his design here, there is no reason (that I can think of) why he couldn't just up the firmware at some point in order to support 24 bit or beyond, but that's just my fairly uneducated opinion.